distributed system help

API

package com.mycompany.eventer;

import io.javalin.Javalin;
import static io.javalin.apibuilder.ApiBuilder.*;

/**
 *
 * @author jens
 */
public class API {

    private final int PORT;

    public API(int port) {
        this.PORT = port;
    }

    public void start() {
        Javalin app = Javalin.create()
                .enableRouteOverview("/routes")
                .enableCorsForAllOrigins()
                .enableAutogeneratedEtags()
                .port(PORT);
        APIHandler handler = new APIHandler();
        setRoutes(app, handler);
        app.start();
    }

    private void setRoutes(Javalin app, APIHandler handler) {
        app.routes(() -> {
            path("/api", () -> {
                //post calls
                post("/create-meetup/:creator/:name/:location/:date/:description/:maxparticipants", handler::createMeetup);
                post("/create-corporateevent/:task/:name/:location/:date/:description/:maxparticipants", handler::createCorporateEvent);
                
            });
            
            get("/get-meetup/:id", handler::getMeetup);

        });
    }
}

APIcaller

package com.mycompany.presentation;

import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;
import com.mashape.unirest.http.exceptions.UnirestException;
import com.mycompany.domain.event.Meetup;
import com.mycompany.domain.event.Task;
import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Date;
import java.util.List;

/**
 *
 * @author jens
 */
public class APIcaller {

    private int port;
    private String ipAddress;

    public APIcaller(int port, String ipAddress) {
        this.port = port;
        this.ipAddress = ipAddress;
    }

    public int getPort() {
        return port;
    }

    public String getIpAddress() {
        return ipAddress;
    }

    public void createMeetup(String creator, String name, String location, Date date, String description, int maxParticipants) {
        String routeUrl = "create-meetup/" + creator + "/" + name + "/" + location + "/" + date + "/" + description + "/" + maxParticipants;
        writeToServer(routeUrl);
    }

    public String getMeetup(int id) throws UnirestException {

        String routeUrl = "get-meetup/" + id;
        String t = getFromServer(routeUrl);
        return t;
    }

    public void createCorperateEvent(List<Task> list, String name, String location, String date, String description, int maxParticipants) {
        StringBuilder builder = new StringBuilder();

        for (Task task : list) {
            builder.append(task.getTaskName());
            builder.append("-");
            builder.append(task.getDescription());
            builder.append("-");
            builder.append(task.isDefault());
            builder.append("§");

        }

        String routeUrl = "create-corporateevent/" + builder.toString() + "/" + name + "/" + location + "/" + date + "/" + description + "/" + maxParticipants;
        writeToServer(routeUrl);
    }

    private boolean writeToServer(String routeUrl) {
        String ipAddress = this.getIpAddress();
        int port = this.getPort();
        String url = "http://" + ipAddress + ":" + port + "/api/" + routeUrl;

        try {
            InetAddress inet = InetAddress.getByName(ipAddress);
            if (inet.isReachable(port)) {
                HttpResponse res = Unirest.post(url).asString();
                
                if (res.getStatus() == 200) {
                    return true;
                }
            }
            System.out.println("GNode did not respond on url: " + url);
            return false;

        } catch (UnirestException ex) {
            ex.getMessage();
            return false;
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return false;
    }

    private String getFromServer(String routeUrl) throws UnirestException {
        String ipAddress = this.getIpAddress();
        int port = this.getPort();
        String url = "http://" + ipAddress + ":" + port + "/api/" + routeUrl;

        try {
            InetAddress inet = InetAddress.getByName(ipAddress);
            if (inet.isReachable(port)) {
                HttpResponse res = Unirest.get(url).asString();
                String body = Unirest.get(url).asString().getBody();

                if (res.getStatus() == 200) {
                    return body;
                }
            }
            System.out.println("GNode did not respond on url: " + url);
            return "";

        } catch (UnirestException ex) {
            ex.getMessage();
            return "";
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return "";
    }
}

APIHandler

package com.mycompany.eventer;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.mycompany.domain.event.EventManager;
import com.mycompany.domain.event.Meetup;
import com.mycompany.domain.event.Task;
import io.javalin.Context;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

/**
 *
 * @author jens
 */
public class APIHandler {

    EventManager eventManager;

    public APIHandler() {
        eventManager = new EventManager();
    }

    public void createCorporateEvent(Context context) {
        try {
            Scanner scanner = new Scanner(context.pathParam("task"));
            Scanner scan;
            String[] stringArray = scanner.delimiter().split("§");
            List<Task> listOfTasks = new ArrayList<>();
            Task task;
            for (String string : stringArray) {
                scan = new Scanner(string);
                String[] taskFromArray = scan.delimiter().split("-");
                if (taskFromArray[2].equals("true")) {
                    task = new Task(taskFromArray[0], taskFromArray[1], true);
                } else {
                    task = new Task(taskFromArray[0], taskFromArray[1], false);
                }
                listOfTasks.add(task);
            }
            
            eventManager.createCorporateEvent(listOfTasks,
                    context.pathParam("name"),
                    context.pathParam("location"),
                    context.pathParam("date"),
                    context.pathParam("description"),
                    Integer.parseInt(context.pathParam("maxparticipants")));
        } catch (NumberFormatException e) {
            context.status(400);
        }

    }

    public void createMeetup(Context context) {
        System.out.println("Route called: addData");
        try {
            eventManager.createMeetupEvent(context.pathParam("creator"),
                    context.pathParam("name"),
                    context.pathParam("location"),
                    context.pathParam("date"),
                    context.pathParam("description"),
                    Integer.parseInt(context.pathParam("maxparticipants")));

        } catch (NumberFormatException e) {
            context.status(400);
        }
    }

    public Meetup getMeetup(Context context) {

        System.out.println("Route called: getData");

        Meetup meetup = eventManager.readMeetupEvent(Integer.parseInt(context.pathParam("id")));

        ObjectMapper mapper = new ObjectMapper();
        if (meetup != null) {
            try {
                context.json(mapper.writeValueAsString(meetup));
            } catch (JsonProcessingException e) {
                context.status(500);
                e.printStackTrace();
            }
        } else {
            context.status(500);
        }

        return null;
    }
}